Universal Human Logic

[John Page]

With no apologies to Chomsky and his Universal Human Grammar and Nagel and his bats :), here's the opening postulation:-

Logic is caused by human brain activity and is a subset of human language and thought (altogether a.k.a.reasoning). While there are variances in brain activity through genetic and experiential effects, there is an underlying common condition (a.k.a. the human condition) that causes and constrains our reasoning. In brief, human reasoning ultimately results from our underlying human condition.

In this way, there exists a Universal Human Logic of which the axioms (the ultimate, unalterable, self-evident rules) are hard-wired into the cognitive apparatus of our brains

This OP was inspired by the following post by Don2. For Godel's reasoning to be correct then Godel himself (since his brain produced his theorems) is part of the 'system' and Universal Human Logic is an a priori determinant of those theorems.

It seems that there is a meta-concept of logic (like formal logic which you and I seem to understand) and then there is an issue of an "implementation" of logic, like particular axioms that are chosen. My perception of logic (which maybe is incorrect) is one of formal logic (more primitive than symbolic logic) beginning with a set Gamma = {thing1, thing2, thing3, thing4}. One might include 'zero' or 'addition' or tautologies like 'modus ponens' or 'modus tollens' in the set of axioms. It all depends. It is easy to conflate axioms thing1, thing2, thing3, thing4 with the meta-framework of logic itself which allows one to begin talking about Gamma to begin with. So, is the higher level framework axiomatic? Does the question even make sense or is it like "is an elephant axiomatic?" My opinion is that there is some sense behind the question and that the framework itself is presumed to be axiomatic and furthermore that there are things outside the scope of logic (because of Goedel's Incompleteness Theorem).

[wnope]

We have yet to find this "universal logic" you refer to if you want an all inclusive one.

Which do you prefer? Greek, Frege, Intuitionist?

Logical axioms are assumed basis for a cognitive heuristic. I don't see how this can lead to a codified version of "logic." It's like saying since we know spoken language we should know how to apply "true" or "false" to various parts. But even that area has problems.

[John Page]

We have yet to find this "universal logic" you refer to if you want an all inclusive one.
Agreed, we don't understand how the human brain works.
Which do you prefer? Greek, Frege, Intuitionist?
None of these. I'm tending toward a logic that is an onward development of predicate logic which a) gets rid of if logical positivist roots, b) incroporates a notation that mirrors the representational nature of mental operations and c) admits dialetheism as a necessary operation since we do not know a priori what is tru and what is not. Another way to look at this is the mind manipulating 'postulated' worlds - I hesitate to say 'possible' worlds since that admits contradictory results could both be true.
Logical axioms are assumed basis for a cognitive heuristic. I don't see how this can lead to a codified version of "logic." It's like saying since we know spoken language we should know how to apply "true" or "false" to various parts. But even that area has problems.
OK. I'm suggesting that the brain is the cause (not quite the right term) of logical axioms. Noumena are themselves brain phenomena. Does that make sense?

[wnope]

Well, all thoughts come from the brain, so I guess so.

But consider that our sense of deductive logic is guided by our inductive learning, not some brain patch (though I'm not excluding compartmentalization).

Learning through experience results in mental confirmation of objects existence (A=A), and that certain results follow from certain actions (A -> B, A = B).

From there we are trying to create a descriptive version of how our brain actually works. It's like trying to formalize a language. We are aiming for something but cannot achieve it perfectly. Deduction is an aid to induction, since with deduction alone you don't gain knowledge.

[John Page]

But consider that our sense of deductive logic is guided by our inductive learning, not some brain patch (though I'm not excluding compartmentalization). ....Deduction is an aid to induction, since with deduction alone you don't gain knowledge.
wnope, Could you expand a little. I'm not familiar with the use of your term "compartmentalization".

[kennethamy]

None of these. I'm tending toward a logic that is an onward development of predicate logic which a) gets rid of if logical positivist roots, b) incroporates a notation that mirrors the representational nature of mental operations and c) admits dialetheism as a necessary operation since we do not know a priori what is tru and what is not.

What are the logical positivist[ic] roots of the predicate logic? I thought that the predicate logic had its roots in classical Aristotelian logic. It it incorporates...mirrors the representational nature of mental operations, it will be a descriptive science, representing how people do think, not how they should think. What good would that be? We know a priori some truths (e.g. that sisters are female siblings) and we know a posteriori other truths (e.g. that Quito is the capital of Ecuador) But even if we did not, why would that necessitate dialetheism?

[John Page]

What are the logical positivist[ic] roots of the predicate logic? I thought that the predicate logic had its roots in classical Aristotelian logic.
They both came out of the analytic era (Frege, Russell etc.) which culminated in the wrong turn of logical positivism demonstrated by Godel and others. It is my contention that the logical positivists influenced how predicate logic was developed leading to similar flaws that discredited logical positivism. Most western philosophy has its roots in classical logic.
'It incorporates...mirrors the representational nature of mental operations, it will be a descriptive science, representing how people do think, not how they should think." What good would that be?
It would provided a phenomenal ontology, i.e. what actually happens, rather than what we think or pustulate happens. The benefits are clearly pragmatic. :)
We know a priori some truths (e.g. that sisters are female siblings) and we know a posteriori other truths (e.g. that Quito is the capital of Ecuador)
The issue is merely how do we know? What makes us think so?
But even if we did not, why would that necessitate dialetheism?
Simply, if one does not know the truth of a matter at the present time the real state of affairs is P v ~P. Later, as a result of brain processing we know (or believe, if you prefer) there is contradictory evidence i.e. the brain might hold the results P & ~P for different postulated situations. You can even read the results on paper for the Liar Paradox.

In summary, I am in no way trying to invalidate or change existing systems of formal logic. What I am trying to do is explore what is really going on. It does not appear reasonable to me that if we invent a new proposition that its truth value automatically exists, this is what I have a problem with. If you have any evidence to show truth values actually exist a priori or come in to existence simulteneously with the creation of a new proposition I'd love to hear about it.

[kennethamy]

They both came out of the analytic era (Frege, Russell etc.) which culminated in the wrong turn of logical positivism demonstrated by Godel and others. It is my contention that the logical positivists influenced how predicate logic was developed leading to similar flaws that discredited logical positivism. Most western philosophy has its roots in classical logic.

It would provided a phenomenal ontology, i.e. what actually happens, rather than what we think or pustulate happens. The benefits are clearly pragmatic. :)

The issue is merely how do we know? What makes us think so?

Simply, if one does not know the truth of a matter at the present time the real state of affairs is P v ~P. Later, as a result of brain processing we know (or believe, if you prefer) there is contradictory evidence i.e. the brain might hold the results P & ~P for different postulated situations. You can even read the results on paper for the Liar Paradox.

In summary, I am in no way trying to invalidate or change existing systems of formal logic. What I am trying to do is explore what is really going on. It does not appear reasonable to me that if we invent a new proposition that its truth value automatically exists, this is what I have a problem with. If you have any evidence to show truth values actually exist a priori or come in to existence simulteneously with the creation of a new proposition I'd love to hear about it.

What flaws were those? And even if they had the same flaws, how would that show they had the same "roots". Does "roots" mean "assumptions", "history", or what does it mean? And, whatever it means, have you any reasons for thinking that it has the same roots (assumptions or history)?

I don't know what you mean by "phenomenal ontology". Did you make up that term?

What makes you think that we do not know that Quito is the capital of Ecuador? I know it. Or that things equal to the same thing are equal to each other? I know it. Or that everything is identical with itself? I know it.

The rest of what you write is even more implausible, or opaque.

[Goathead]

I say that Language must extend from Logic, and not necessarily the other way around. (language is only the codified utterance of a naked ape, it requires order which requires reason and memory).

[John Page]

What flaws were those? And even if they had the same flaws, how would that show they had the same "roots". Does "roots" mean "assumptions", "history", or what does it mean?
This is a work in progress. I think there are category errors in the definition of systems of predicate logic that make no sense for a physical implementation. I say this from the point of view of having implemented actual systems. Complex ones involving real-time databases.
And, whatever it means, have you any reasons for thinking that it has the same roots (assumptions or history)?
The simple fact that our descriptions of how we think are not actually how we think.
I don't know what you mean by "phenomenal ontology". Did you make up that term?
Yes. It means an ontology that accords to actual phenomena as opposed to a hypothetical ontology of being.
What makes you think that we do not know that Quito is the capital of Ecuador? I know it. Or that things equal to the same thing are equal to each other? I know it. Or that everything is identical with itself? I know it.
These are not new propositions. How about "President Bush thinks that Gonzales should not resign because the Constitution has the blessing of god and therefore Bush has the delegated authority of god." Do you know absolutely whether P v ~P?
The rest of what you write is even more implausible, or opaque.
More implausible than what? Systems of logic that result in contradictions which are contrary to the foundational principles of logic?

Gotta go......

[kennethamy]

T

These are not new propositions. How about "President Bush thinks that Gonzales should not resign because the Constitution has the blessing of god and therefore Bush has the delegated authority of god." Do you know absolutely whether P v ~P?

..

I don't know at all, absolutely or not, whether that proposition is true, but I tend to doubt it. You might want to explain what it means to "know absolutely". If you mean "know with infallible certainty,so that no error is possible" there is very little if anything I know that meets that standard:maybe that I exist. But if that is your standard for knowledge, then no one knows much of anything. Not even that salt is sodium chloride.

[Witt]

John Page: "Do you know absolutely whether P v ~P?"

Are you saying that there are absolute truths??

If so, how could you know it?

[JamesBannon]

I can't see how logic can be "hard-wired" when it wasn't even known for much of human history, unless you count trial-and-error learning as logic.

[kennethamy]

I can't see how logic can be "hard-wired" when it wasn't even known for much of human history, unless you count trial-and-error learning as logic.

Well, what was not known was the theory of logic until Aristotle who practically invented it. But, as the philosopher John Locke wrote, "God did not give men two legs, and leave it up to Aristotle to make them logical". People used logic and arguments before Aristotle. Just as people played chess before chess theory was established, and chess books were written.

[John Page]

I don't know at all, absolutely or not, whether that proposition is true, but I tend to doubt it.
OK. Now let's say this is an accurate statement of the affairs of your mind. Seems that we have:

a) a contingent or probabalistic truth (because of the remaining doubt) and

b) a consequent rejection of the LEM in analysis of sentential propositions.

Do you think a) and b) are fair statements?

[kennethamy]

OK. Now let's say this is an accurate statement of the affairs of your mind. Seems that we have:

a) a contingent or probabalistic truth (because of the remaining doubt) and

b) a consequent rejection of the LEM in analysis of sentential propositions.

Do you think a) and b) are fair statements?

I haven't rejected LEM. I believe it is true.

And I doubt the Bush proposition is true. So I clearly don't know it. (And it isn't a contingent truth if it is false, and it isn't contingent because I doubt it, and I don't know what a probabilistic truth is supposed to be. (If you mean it is probable that the Bush proposition is true, I deny that).

Where is this going? If anywhere? (Is this you trying the Socratic method, or have you any idea where you are headed?)

[TruthPrevails]

I don't know at all, absolutely or not, whether that proposition is true, but I tend to doubt it. You might want to explain what it means to "know absolutely". If you mean "know with infallible certainty,so that no error is possible" there is very little if anything I know that meets that standard:maybe that I exist. But if that is your standard for knowledge, then no one knows much of anything. Not even that salt is sodium chloride.Maybe you are familiar with 'confidence levels' and not applying that to practical life. If not, take a course in Statistics 101.

[John Page]

I haven't rejected LEM. I believe it is true.

And I doubt the Bush proposition is true. So I clearly don't know it. (And it isn't a contingent truth if it is false, and it isn't contingent because I doubt it, and I don't know what a probabilistic truth is supposed to be. (If you mean it is probable that the Bush proposition is true, I deny that).
Given your statements above, I don't see how you can maintain that LEM is true. Even if you doubt that the Bush proposition is true you are admitting that it might be true. True?

Surpirsingly to me you are denying contingency (P v ~P). This being the case, I think you are implicitly agreeing that P & ~P because of your lack of certain knowledge. The only way forward I can see for your position is that P is partially true or partially false - from which I can impute a % probability. How else would you characterize your position?

Where is this going? If anywhere? (Is this you trying the Socratic method, or have you any idea where you are headed?)
Toward the development of a Universal Human Logic. :)

Seriously, I have two major points to inject once we have completed this piece of dialog.

[John Page]

John Page: "Do you know absolutely whether P v ~P?"

Are you saying that there are absolute truths??

If so, how could you know it?
I was question begging. :)

In return, can I ask you if we were able to deterministically treat truth, so it would become like a property of a substance, wouldn't we then be able know an truth absolutely? (Note, not an absolute truth - please be patient with me).

[kennethamy]

Maybe you are familiar with 'confidence levels' and not applying that to practical life. If not, take a course in Statistics 101.

Don't see what that has to do with it. I just said that there is very little if anything I know so that it would be impossible for me to be mistaken, and if that is your standard of knowledge, the impossibility of error, then I do not even know that salt is sodium chloride. Is that your standard of knowledge? That is a question in plain English. You should (if you are a native speaker) be able to answer it, without technical jargon.

[John Page]

I say that Language must extend from Logic, and not necessarily the other way around. (language is only the codified utterance of a naked ape, it requires order which requires reason and memory).
Hadn't thought about that before. In the Chomskian sense you are probably right because in his position grammar is an intrinsic part of any language. So, without the reason required to process grammar our communications are merely signals, not language at all.

[premjan]

Logic can't really precede language as language is innate - babies pick it up without coaching, and logic generally requires some training. Logic is maybe implicitly present in the brain but learning explicit logic requires study.

[John Page]

I can't see how logic can be "hard-wired" when it wasn't even known for much of human history, unless you count trial-and-error learning as logic.
I should have made this clearer that I meant hard-wired in the sense of deterministically caused, not hard-wired in the sense of pre-determined or designed.

[kennethamy]

Given your statements above, I don't see how you can maintain that LEM is true. Even if you doubt that the Bush proposition is true you are admitting that it might be true. True?

Surpirsingly to me you are denying contingency (P v ~P). This being the case, I think you are implicitly agreeing that P & ~P because of your lack of certain knowledge. The only way forward I can see for your position is that P is partially true or partially false - from which I can impute a % probability. How else would you characterize your position?


Toward the development of a Universal Human Logic. :)

Seriously, I have two major points to inject once we have completed this piece of dialog.

LEM says that either p is true or the negation of p is true. Why is that inconsistent with saying that the Bush proposition might be true? I am just saying that given my all information, it is unlikely that the proposition is true. That is not inconsistent with its being true.

Denying contingency of what? I wonder whether you know what it means to say of a proposition that it is a contingent proposition. It means that its negation is logically possible. I think you may be confusing the epistemic sense of "might be true" with the metaphysical/logical sense of "might be true". The first sense just means "for all I know, it might be true (that p)" The other sense means, "the negation is logically possible". Two different senses of. "it might be true".

[John Page]

Logic can't really precede language as language is innate - babies pick it up without coaching, and logic generally requires some training. Logic is maybe implicitly present in the brain but learning explicit logic requires study.
Hi premjan. I think there is confusion here about which logic. I don't mean classical logic. A couple of points:

1. There are certain syntactical aspects of human language that seem to be innate. This is Chomsky's Universal Human Grammar (UHG). Obviously some components of language vary since multiple languages exist.
2. I am trying to make a similar argument for a Universal Human Logic (UHL)which would roughly equate to what you say may be "implicitly in the brain".

It would seem to me that UHL would predate UHG because we must cognize before we verbalize? Does this make sense to you?

[premjan]

Maybe logic is a subset of grammar. But people do vary a lot in their ability / inclination to be logical. Also XOR is hard to simulate with a neural net. But some sort of ability for basic logical properties (such as transitivity, commutativity, inference etc.) probably does exist.

[John Page]

LEM says that either p is true or the negation of p is true. Why is that inconsistent with saying that the Bush proposition might be true? I am just saying that given my all information, it is unlikely that the proposition is true. That is not inconsistent with its being true.
I am not talking about what might be shown at a future point in time. I am trying to nail down the current state of affairs. Right now you are saying that in the future it might be shown that P v ~P. This is consistent with them LEM and I have no problem with this.

However, right now you don't know the future. Therefore the current truth value is somewhat P and somewhat ~P based on the available evidence. This reduces to P & ~P being the state of affairs.
Denying contingency of what? I wonder whether you know what it means to say of a proposition that it is a contingent proposition. It means that its negation is logically possible.
To clarify, I used contingency to refer to the truth value of the proposition, not a contingent proposition.

[kennethamy]

I am not talking about what might be shown at a future point in time. I am trying to nail down the current state of affairs. Right now you are saying that in the future it might be shown that P v ~P. This is consistent with them LEM and I have no problem with this.

However, right now you don't know the future. Therefore the current truth value is somewhat P and somewhat ~P based on the available evidence. This reduces to P & ~P being the state of affairs.

To clarify, I used contingency to refer to the truth value of the proposition, not a contingent proposition.

The truth value of a proposition is independent of anyone's knowledge of its truth value. (I have no idea what "somewhat p" means. Do you make these things up at the spur of the moment?

Again, I have no idea what it would mean for the truth value of a proposition to be contingent. Propositions are contingent or they are necessary. Again, same question. Do you make up these terms as phrases as you go along?

To communicate our languages have, at least, to overlap. You make up phrases I have never heard of, and you somehow expect me to know what you mean by them (if anything at all). Your Humpty-Dumpty view of language is a big problem. And so is your ignorance of philosophy

[John Page]

The truth value of a proposition is independent of anyone's knowledge of its truth value.
There is no support for this assertion and, anyway, how do you know this to be true?
(I have no idea what "somewhat p" means.
I posted "somewhat P" i.e. uppercase which you would well understand that P means the proposition in question is true. By somewhat P I therefore meant that it is somewhat the case that the proposition in question is true.
Do you make these things up at the spur of the moment?
No. You might wish to become more widely read.
Again, I have no idea what it would mean for the truth value of a proposition to be contingent.
:Cheeky: Sorry, can't help you there. What do you think the truth value of a proposition is contingent upon?
Propositions are contingent or they are necessary. Again, same question. Do you make up these terms as phrases as you go along?
You don't seem to read, do you? As in my previous post, I am not talking about contingent propositions.
To communicate our languages have, at least, to overlap. You make up phrases I have never heard of, and you somehow expect me to know what you mean by them (if anything at all).
Dialetheism.
Your Humpty-Dumpty view of language is a big problem.
Mean anything specific here?
And so is your ignorance of philosophyAd hominem. If you are going to continue lapsing into a dogmatic, negative behavior trait there is no point in you posting.

[John Page]

I'd be very interested in comments on the following view that current languages of logic are demonstrably inadequate for expressing the operation of logic (which includes one's brain's manipulation of formal system notation).

At time t1 Tommy is holding the cup. At time t2 Tommy is not holding the cup. The proposition T, "Tommy is holding the cup", is true at time t1 and false at time t2.

The languages of neither classical logic nor predicate logic allow analysis of such situations. Humans have no trouble in understanding that truth values may vary over time because the facts may vary over time.

From this example, it is proposed that Universal Human Logic (UHL) incorporates variability over time and that any attempt to develop a notation and semantic structure to represent UHL must incorporate the concept of time.

[kennethamy]

There is no support for this assertion and, anyway, how do you know this to be true?

I posted "somewhat P" i.e. uppercase which you would well understand that P means the proposition in question is true. By somewhat P I therefore meant that it is somewhat the case that the proposition in question is true.

No. You might wish to become more widely read.

:Cheeky: Sorry, can't help you there. What do you think the truth value of a proposition is contingent upon?

You don't seem to read, do you? As in my previous post, I am not talking about contingent propositions.

Dialetheism.

Mean anything specific here?
Ad hominem. If you are going to continue lapsing into a dogmatic, negative behavior trait there is no point in you posting.

Because the truth value of "there are an odd number of grains of sand on Wakiki Beach in Hawaii", is either true or false, but no one knows whether that proposition is true or false. Therefore, that is a proposition whose truth value is independent of whether anyone knows it is true or false. Q.E.D.

The truth value of a proposition is contingent on whether the proposition is true or false. Of course.

[John Page]

Because the truth value of "there are an odd number of grains of sand on Wakiki Beach in Hawaii", is either true or false, but no one knows whether that proposition is true or false.
Therefore, right here, right now, the fact is that the proposition is neither truth nor false and whether the LEM applies is a matter of conjecture.
The truth value of a proposition is contingent on whether the proposition is true or false. Of course.
LOL. It is dependent upon the system of truth determination you apply. My point is that a proposition is not a priori true, false or any other logical value.

[kennethamy]

Therefore, right here, right now, the fact is that the proposition is neither truth nor false and whether the LEM applies is a matter of conjecture.

LOL. It is dependent upon the system of truth determination you apply. My point is that a proposition is not a priori true, false or any other logical value.

If that means that we don't know, it is. But I thought that you denied that knowledge of the truth is independent of the truth, And my example of the sands of Wakiki shows you are wrong. So why are you diverting the subject?

I can but repeat that in answer to your question, on what is the truth value of a proposition contingent, my answer is that it is contingent on whether the proposition is true or false. Every proposition is either true or false. Whether it is true, or whether it is false, depends, in the case of contingent propositions, on the facts as they are. In the case of a priori propositions, it depends on how the truth values of such propositions are decided. For instance, in the case of the a priori proposition, all bachelors are unmarried males, it depends on the meanings of the terms involved.

[John Page]

If that means that we don't know, it is. But I thought that you denied that knowledge of the truth is independent of the truth, And my example of the sands of Wakiki shows you are wrong. So why are you diverting the subject?
I am not diverting. I am trying to understand your position which seems contradictory to me for the foregoing reasons. If, to quote you "that means that we don't know, it is." then there is no basis for claiming LEM is true (lack of knowledge).

Where did I deny knowledge of the truth is independent of the truth? :confused:
Every proposition is either true or false. Whether it is true, or whether it is false, depends, in the case of contingent propositions, on the facts as they are. In the case of a priori propositions, it depends on how the truth values of such propositions are decided. For instance, in the case of the a priori proposition, all bachelors are unmarried males, it depends on the meanings of the terms involved.
So you redefine the terms to suit the logic? I'm fine with tautologies but not all statements are tautologies. What do you mean by "the a priori proposition"?

[kennethamy]

I am not diverting. I am trying to understand your position which seems contradictory to me for the foregoing reasons. If, to quote you "that means that we don't know, it is." then there is no basis for claiming LEM is true (lack of knowledge).

Where did I deny knowledge of the truth is independent of the truth? :confused:

So you redefine the terms to suit the logic? I'm fine with tautologies but not all statements are tautologies. What do you mean by "the a priori proposition"?

Any proposition can be true whether or not we know that it is true. LEM is a logical truth, and can be shown to be one by putting it on a truth table.

I don't know which terms you claim I have redefined. So I can't reply intelligently. But I am unaware of any terms I have redefined.

The term "a priori" in philosophy means, "known independently of observation". So, an a priori proposition is a proposition whose truth or falsity is known independently of observation. LEM is an example of an a priori proposition.

You are correct, some statements or propositions are not tautologies. And some are. LEM is one.

"Where did I deny knowledge of the truth is independent of the truth? :confused:"

I wrote:

"The truth value of a proposition is independent of anyone's knowledge of its truth value."

You replied:

"There is no support for this assertion and, anyway, how do you know this to be true?"

[John Page]

Any proposition can be true whether or not we know that it is true. LEM is a logical truth, and can be shown to be one by putting it on a truth table.
So you say. Depends on Law of Identity.
....it depends on the meanings of the terms involved.
So you redefine the terms to suit the logic?
I don't know which terms you claim I have redefined. So I can't reply intelligently. But I am unaware of any terms I have redefined.
The point is that I have stated a proposition you can't tell me the truth of. The only way that you can do so is by changing "...the meanings of the terms involved".
The term "a priori" in philosophy means, "known independently of observation". So, an a priori proposition is a proposition whose truth or falsity is known independently of observation. LEM is an example of an a priori proposition.
I dispute this definition. Independently of (prior) experience. LEM is clearly synthetic and its truth value is not known a priori as per my examples. You cannot turn a law of classical logic into a panacea for all logic by diktat. T = P v ~P does not admit 0.5 T = P & ~P. Imagination is required.
I wrote:

"The truth value of a proposition is independent of anyone's knowledge of its truth value."

You replied:

"There is no support for this assertion and, anyway, how do you know this to be true?"
Still waiting for an answer as to how you know something you don't know.

[kennethamy]

So you say. Depends on Law of Identity.



The point is that I have stated a proposition you can't tell me the truth of. The only way that you can do so is by changing "...the meanings of the terms involved".

I dispute this definition. Independently of (prior) experience. LEM is clearly synthetic and its truth value is not known a priori as per my examples. You cannot turn a law of classical logic into a panacea for all logic by diktat. T = P v ~P does not admit 0.5 T = P & ~P. Imagination is required.

Still waiting for an answer as to how you know something you don't know.

I didn't say that LEM depends on the law of identity.
What do you mean you "dispute that definition"? That is what "a priori" means.
"existing in the mind prior to and independent of experience, as a faculty or character trait. Compare a posteriori (def. 2)." (dictionary).
LEM is synthetic? How could it be synthetic if it is a tautology? You just don't know what these terms mean. "Synthetic" means " the negation is not self-contradictory". It is the opposite of "analytic" Get yourself a philosophical dictionary. You cannot make up the meanings ad libitum

"The point is that I have stated a proposition you can't tell me the truth of. The only way that you can do so is by changing "...the meanings of the terms involved".

No idea what you are talking about. Which proposition? The meanings of what words?

I cannot both know and not know something. That would be a contradiction. So what on earth makes you ask that question?

I can know of a proposition, but not know whether it is true or false. Is that what you mean? You are a native speaker of English aren't you? When did I assert I could both know and not know a proposition was true?

[John Page]

I didn't say that LEM depends on the law of identity.
No, I did. It depends on how you interpret it.
What do you mean you "dispute that definition"? That is what "a priori" means.
"existing in the mind prior to and independent of experience, as a faculty or character trait. Compare a posteriori (def. 2)." (dictionary).
Thank you, you had posted that a priori was about observation, not experience. To experience somehting, it must have happened beforehand. This is why I'm asking again whether made up propositions have truth values before they're made up.

LEM is synthetic? How could it be synthetic if it is a tautology? You just don't know what these terms mean. "Synthetic" means " the negation is not self-contradictory". It is the opposite of "analytic" Get yourself a philosophical dictionary. You cannot make up the meanings ad libitum
But I didn't make them up, I'm just poking holes in them. Synthetic means determined by observation or fact. Analytic means necessarily true independent of fact or experience. My view (as you've probably guessed by now) is that logic is a human brain process. From this view it follows that anything a priori propositions are just propositions and until they've been processed there is no ensuing knowledge of truth.

Are you maintaining that the laws of propositional logic were true before anybody even thought of them? From the references you quote and approach to this topic is, I believe you are biased by the direction of the Analytic philosophers which resulted in the failure of logical positivism. Furthermore, any attempt to show the laws of logic are a priori 'true' prior to human experience will fail in the same manner as St. Anslem's ontological proof of the existence of god - somewhat the legacy which the analytic's inherited.
I cannot both know and not know something. That would be a contradiction. So what on earth makes you ask that question?

I can know of a proposition, but not know whether it is true or false. Is that what you mean? You are a native speaker of English aren't you? When did I assert I could both know and not know a proposition was true?
When you posted..."The truth value of a proposition is independent of anyone's knowledge of its truth value."
A truth value is knowledge hence the contradiction.

[kennethamy]

But I didn't make them up, I'm just poking holes in them. Synthetic means determined by observation or fact. Analytic means necessarily true independent of fact or experience. .

You are wrong.
"Synthetic" means (according to Kant who coined the word) the predicate is not contained in the subject. "Analytic" means (according to Kant who coined the word), the predicate is contained in the subject. You are confusing "analytic" with "known a priori" and "synthetic" with "known a posteriori".

Get a philosophical dictionary.

[John Page]

You are wrong.
"Synthetic" means (according to Kant who coined the word) the predicate is not contained in the subject. "Analytic" means (according to Kant who coined the word), the predicate is contained in the subject. You are confusing "analytic" with "known a priori" and "synthetic" with "known a posteriori".

Get a philosophical dictionary.
My definitions are accurate. Analytic: predicate is contained in the subject which means it is necessarily true. Synthetic: predicate is not contained in the subject meaning we must resort to observation and fact.

Instead of a war of dictionaries (I checked my definition to be accurate with a reliable dictionary source before quoting it and I now have two definitions of synthetic from you), and irrespective of my faithfulness to Kant, I'll just observe that you're still missing the point. Logical operations are performed by the brain. LEM is synthetic; observation reveals that not all propositions are true or false.

How about a semi-liar? This sentence is half true. This contradicts LEM which, therefore, is not a tautology as you claim.

[kennethamy]

My definitions are accurate. Analytic: predicate is contained in the subject which means it is necessarily true. Synthetic: predicate is not contained in the subject meaning we must resort to observation and fact.



Kant held that there were synthetic a-priori propositions. Propositions whose predicates are not contained in their subjects, but which could be known only without observation. For instance, all mathematical propositions, or the proposition that every event must have a cause. And Saul Kripke holds that there are analytic necessary truths that can be known a posteriori. In fact, Kant held that the possibility of their being synthetic a priori propositions was, and I quote, "a matter of life or death for philosophy".

I am afraid there is no help for it. You will simply have to learn some philosophy.

[John Page]

Originally Posted by John Page
My definitions are accurate. Analytic: predicate is contained in the subject which means it is necessarily true. Synthetic: predicate is not contained in the subject meaning we must resort to observation and fact.

Kant held that there were synthetic a-priori propositions. Propositions whose predicates are not contained in their subjects, but which could be known only without observation. For instance, all mathematical propositions, or the proposition that every event must have a cause.
Doesn't look like you read my post.
And Saul Kripke holds that there are analytic necessary truths that can be known a posteriori. In fact, Kant held that the possibility of their being synthetic a priori propositions was, and I quote, "a matter of life or death for philosophy".
I have read Kant in detail, particularly Critique of Pure Reason. What would he have made of Libet's findings, I wonder.

I just find it very strange that someone who resists so strongly that logic is in the brain and that memories are in the brain is perfectly happy with definitions like "Propositions whose predicates are not contained in their subjects." A far better wording would perhaps be "Propositions whose predicate falls within the definiton of the subject."

But this is a distraction from the LEM, which is synthetic. If you insist on binary logic you might have a case but then I might as well talk to my computer.

[Don2 (Don1 Revised)]

Kant held that there were synthetic a-priori propositions. Propositions whose predicates are not contained in their subjects, but which could be known only without observation. For instance, all mathematical propositions, or the proposition that every event must have a cause.
The truthfulness of any mathematical proposition X in the context of any logical system Y is dependent upon the axioms y in Y such that X can or cannot be proven from them. For any putative logical system Y, it is humans that choose y in Y as the axioms. So, is there a substantive difference between these theoretical mathematical propositions which "could be known only without observation" and their true nature which is as human-invented abstractions? Is there particularly a substantive difference with respect to the op?

And Saul Kripke holds that there are analytic necessary truths that can be known a posteriori. In fact, Kant held that the possibility of their being synthetic a priori propositions was, and I quote, "a matter of life or death for philosophy".
I think he meant the tautology that "a priori human propositions are a necessity for a priori human philosophy."

[kennethamy]

I think he meant the tautology that "a priori human propositions are a necessity for a priori human philosophy."

I doubt that. He was replying to Hume's attack on traditional metaphysics which consigned it to the flames. I am sorry, but I do not know what a "human proposition" is. (How could that be a tautology, anyway?)

[John Page]

(How could that be a tautology, anyway?)
Proposition = predicate, philosophy = subject.

[kennethamy]

Proposition = predicate, philosophy = subject.

Sorry. :huh:

[John Page]

"Analytic" means (according to Kant who coined the word), the predicate is contained in the subject.
Originally Posted by Don2 (Don1 Revised)
I think he meant the tautology that "a priori human propositions are a necessity for a priori human philosophy."
I doubt that.... (How could that be a tautology, anyway?)

Proposition = predicate, philosophy = subject.
Sorry. :huh:
All analytic statements are tautologies (after Kant).

[kennethamy]

All analytic statements are tautologies (after Kant).

How did that statement turn out to be analytic? (I won't even go into the issue of the distinction between analytic statements and tautologies except to point out that tautologies can be shown to be such on a truth table, and analytic statements cannot. So all tautologies are analytic, but not conversely).

[John Page]

How did that statement turn out to be analytic? (I won't even go into the issue of the distinction between analytic statements and tautologies except to point out that tautologies can be shown to be such on a truth table, and analytic statements cannot. So all tautologies are analytic, but not conversely).
All propositions are contained in philosophy.

[kennethamy]

All propositions are contained in philosophy.

Of course.:huh: :huh: There is no obligation for you to post if you have nothing to say.

[John Page]

Of course.:huh: :huh: There is no obligation for you to post if you have nothing to say.
LOL. So there is no obligation to post tautologies?

[John Page]

NEW SUBTOPIC COMING UP

I'm just putting together a post under this UHL thread to start discussion of Russell's theory of types (in particular the predicate heirarchy he applied) and its relevance to natural(?) human thought.

Start deep brain stimulation now! Feel free to pre-empt.

[kennethamy]

LOL. So there is no obligation to post tautologies?

1. There is no obligation to post at all.
2. Posting tautologies is posting.

Therefore, 3. (I suppose you can draw the conclusion yourself).

[John Page]

1. There is no obligation to post at all.
2. Posting tautologies is posting.

Therefore, 3. (I suppose you can draw the conclusion yourself).
That may well be true, but its not what you posted, you said...
There is no obligation for you to post if you have nothing to say.
Tautologies say nothing in the sense that they are vacuous.

So "Tautologies are vacuous" is a vacuous tautology. Now that's saying something!